Circadian Rhythms and the Tick-Tock of Your Baby’s Biological Clock

Circadian Rhythms and Your Baby

Something I explain to my new parents with babies younger than 4 months of age, is about their baby’s biological clock and circadian rhythms.  You’ve all heard that from me right?  ”Their biological clock hasn’t matured yet, therefore…” So I thought it would be a good idea if I explained this in more detail as it is such a huge component in your newborns 4th trimester sleep milestones, not to mention the fundamentals of healthy sleep.  There is going to be some boring science talk below, sorry about that, but I think to fully understand what I mean when I speak about biological clocks and natural sleep rhythms, you should fully understand what the heck they are!

The time your child sleeps is just as, if not more important, then how long your child sleeps.  Remember healthy sleep is the right amount of sleep, at the right time, for the right consolidated length.  We want to synch our sleep with our natural circadian rhythms so that we get the best restorative sleep possible.  Our biological clocks or internal 24-hour sleepy clocks as I sometimes call them, are genetically controlled.  These clocks drive our circadian rhythms and tell our bodies when we should be sleeping.

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Circadian..whaaa?  Let’s talk a bit about what circadian rhythms are.  Don’t let me lose you now.

Our circadian rhythms follow a 24-hour clock and control our physical, mental and behavioral changes.  They are largely cued by our external environment with the main cue being the dark (night) and light (day).  These cues influence our circadian rhythms, which drive our internal clocks (sleep drive).  When it’s darker outside we are more tired, i.e. our sleep drive is stronger.  Sleep-wake cycles, hormone release, body temperature and other important bodily functions can all be affected by circadian rhythms.  Our sleep patterns and our children’s sleep patterns are determined by our circadian rhythms.

These 24-hour biological clocks has a “master clock”, which is a group of nerve cells in the brain (with a big name that I’m not going to bore you with).  The master clock is located in an area of the brain just above the optic nerves and it coordinates all the body clocks so that they are in synch.  It is because of this that the light and dark of the day is the biggest cue.  When our eyes see darkness it cues the brain to release melatonin, a natural sleep hormone, that makes us drowsy.  This is why a consistent bedtime routine is so important!  Dimming the lights, darkening the room, helps release the melatonin to help you to fall asleep.

3-6 month sleep tips

Here is why educating parents on their child’s biological clock and natural sleep flows (rhythms) are important and one of the major components in my Sleep Plans.  When your child sleeps in synch with their circadian rhythms they are able to get the most restorative and better quality sleep.  Here is how I explain it to my parents.  We should (though, who are we kidding, it never happens) be getting at least 8 hours of sleep per night.  So that 8 hours is the “right amount of sleep and at the right consolidated length” part of healthy sleep.  Now if we were to sleep from 3pm to 11pm at night, we’d be getting the right amount of sleep at the right consolidated length, right?  But if we were up from 11pm to 3 in the afternoon the next day, I don’t know about you guys but I would be a complete wreck.  Why?  Because even though I’m getting that 8 hours, I’m not sleeping at the right time of day.  My sleep isn’t synched with my natural sleep flow, or circadian rhythms.  This is similar to when you’re experiencing jet-lag, or struggling with shift-work.  So even though I’m sleeping I still could be accumulating a sleep debt.

So if you pair sleep synched with your childs natural sleep flow, and a 
continuous (consolidated) sleep, your child will be getting the best restorative sleep possible.  When I build a routine and schedule for my parents they are based on their childs natural sleep flow for their biological age.

It’s difficult to start sleep training an infant before 4 months of age because at this point their biological clock hasn’t matured. It takes time for a baby to develop his own natural circadian rhythm.  You have to keep in mind he was just in your womb that stayed dark for 24/7.  Sleep patterns develop with time, and as the baby get’s older their biological clock and nervous system matures, which makes getting them on a routine and learning to soothe themselves much easier.  There are steps that you can take in the first few months that make setting your babies biological clock easier.

  • Letting sunlight into the room in the morning will help a baby learn to wake at the right time.
  • Dimming lights in the evening also helps.
  • Having a regular feeding and activity schedule makes setting a baby’s biological clock easier.

The first component of healthy sleep is learning to respect your child’s circadian rhythms and in order to do this you need to determine where the child is biologically.  In order to do this you would start your sleep timeline at your baby’s estimated due date.  That is when their biological age starts, even if they were born before their EDD.  For example, if your baby was early by 1 month then you would start taking his age into account from his EDD not the day he was born.  Instead of being 2 months old, biologically he is 1 month old.  It’s important to know when you should start seeing signs of their sleep rhythms and internal clocks kicking into gear.

Parents enjoy your new baby.  Know that this time in your lives is short, and let go of unrealistic expectations.

Circadian Rhythms Fact Sheet – National Institute of General Medical Sciences – http://www.nigms.nih.gov.



Alanna McGinn is a Certified Infant and Toddler Sleep Consultant and Founder of Good Night Sleep Site – a Global Pediatric and Family Sleep Team. She provides free child and family sleep support through her FacebookTwitter, and Instagram. She invites you to join her sleep community as she works towards Good Night Sleep Site’s mission of a healthier rested family unit. For more sleep tips please visit Good Night Sleep Site.

Alanna McGinn
Alanna McGinn
Alanna McGinn is Founder and Certified Sleep Expert of Good Night Sleep Site, a global sleep consulting practice. She is host of the ‘This Girl Loves Sleep’ Podcast and author of ‘This Baby Loves Sleep’. Alanna has established the world-wide brand of Good Night Sleep Site as being a #1 sleep resource for families and her and her team of sleep consultants strive in helping families (baby to adults) and corporations overcome their sleep challenges and have well-rested smiles in the morning. You can find out more about Alanna McGinn and how to work with a Good Night Sleep Consultant at www.goodnightsleepsite.com and follow Alanna and all her sleep tips on Instagram - @GNSleepSite.

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